Occult Vascular Malformations and Seizures

Bipolar Electrocoagulation on Cortex after AVMs Lesionectomy for Seizure Control

Background:

The findings of previous studies remain controversial on the optimal management required for effective seizure control after surgical excision of arteriovenous malformations (AVMs). We evaluated the efficacy of additional bipolar electrocoagulation on the electrically positive cortex guided by intraoperative electrocorticography (ECoG) for controlling cerebral AVMs-related epilepsy.

Clinical Material and Methods:

Sixty consecutive patients with seizure due to cerebral AVMs, who underwent surgical excision of cerebral AVMs and intraoperative ECoG, were assessed. The AVMs and surrounding hemosiderin stained tissue were completely removed, and bipolar electrocoagulation was applied on the surrounding cerebral cortex where epileptic discharges were monitored via intraoperative ECoG. Patients were followed up at three to six months after the surgery and then annually. We evaluated seizure outcome by using Engel's classification and postoperative complications.

Results:

Forty-nine patients (81.6%) were detected of epileptic discharges before and after AVMs excision. These patients underwent the removal of AVMs plus bipolar electrocoagulation on spike-positive site cortex. After electrocoagulation, 45 patients' epileptic discharges disappeared, while four obviously diminished. Fifty-five of 60 patients (91.7%) had follow-up lasting at least 22 months (mean 51.1 months; range 22-93 months). Determined by the Engel Seizure Outcome Scale, 39 patients (70.9%) were Class I, seven (12.7%) Class II, five (9.0%) Class III, and four (7.2%) Class IV.

Conclusions:

Even alter the complete removal of AVM and sunwinding gliolic and hemosiderin stained tissue, a high-frequency residual spike remained on the surrounding cerebral cortex. Effective surgical seizure control can be achieved by carrying on I additional bipolar electrocoagulation on the cortex guided by the intraoperative ECoG.

High-frequency oscillations detected in ECoG recordings correlate with cavernous malformation and seizure-free outcome in a child with focal epilepsy: A case report

Epilepsy associated with cavernous malformation (CM) often requires surgical resection of seizure focus to achieve seizure‐free outcome. High‐frequency oscillations (HFOs) in intracranial electroencephalogram (EEG) are reported as potential biomarkers of epileptogenic regions, but to our knowledge there are no data on the existence of HFOs in CM‐caused epilepsy. Here we report our experience of the identification of the seizure focus in a 3‐year‐old pediatric patient with intractable epilepsy associated with CM. The electrocorticographic recordings were obtained from a 64‐contact grid over 2 days in the epilepsy monitoring unit (EMU). The spatial distribution of HFOs and epileptic spikes were estimated from recording segments right after the electrode placement, during sleep and awake states separately. The HFO distribution showed consistency with the perilesional region; the location of spikes varied over days and did not correlate with the lesion. The HFO spatial distribution was more compact in sleep state and pinpointed the contacts sitting on the CM border. Following the resection of the CM and the hemosiderin ring, the patient became seizure‐free. This is the first report describing HFOs in a pediatric patient with intractable epilepsy associated with CM and shows their potential in identifying the seizure focus.

Surgical treatment of epilepsy

PURPOSE OF REVIEW

This article outlines indications for neurosurgical treatment of epilepsy, describes the presurgical workup, summarizes surgical approaches, and details expected risks and benefits.

RECENT FINDINGS

There is class I evidence for the efficacy of temporal lobectomy in treating intractable seizures, and accumulating documentation that successful surgical treatment reverses much of the disability, morbidity, and excess mortality of chronic epilepsy.

SUMMARY

Chronic, uncontrolled focal epilepsy causes progressive disability and increased mortality, but these can be reversed with seizure control. Vigorous efforts to stop seizures are warranted. If two well-chosen and tolerated medication trials do not achieve seizure control, an early workup for epilepsy surgery should be arranged. If this workup definitively identifies the brain region from which the seizures arise, and this region can be removed with a low risk of disabling neurologic deficits, neurosurgery will have a much better chance of stopping seizures than further medication trials.

Long-term seizure control after resection of supratentorial cavernomas: a retrospective single-center study in 53 patients

OBJECTIVE

The goal of this study was to examine the long-term outcomes of 53 epilepsy patients who were surgically treated for supratentorial cavernomas in a single-center study and to assess both the duration of epilepsy and the resection of the hemosiderin rim for their prognostic relevance during extended follow-up.

METHODS

Fifty-three patients underwent microsurgical resection of radiologically diagnosed supratentorial cavernomas. For the outcome analysis, they were divided into 2 groups: Group A (33 patients) with a preoperative duration of epilepsy of less than 2 years, and Group B (20 patients) with a preoperative duration of epilepsy of 2 years or more. The natural history of the cavernomas, localization and size of the lesions, use of antiepileptic drugs, surgery timing, and technique (removal or not of the surrounding gliosis) were evaluated retrospectively. The outcome of epilepsy was based on Engel's classification and the International League Against Epilepsy classification.

RESULTS

After a mean follow-up period of 8.1 years, 45 (84.9%) of the 53 patients were free from disabling seizures (Engel Class I), including 37 patients (69.8%) who were completely free of postoperative seizures (Engel Class IA); 43 patients (81.1%) were categorized as International League Against Epilepsy Class 1. Outcome was statistically significantly improved in the patient subgroup of our study in which patients underwent a resection of the surrounding gliosis after a preoperative duration of epilepsy of less than 2 years (Group A). There was no mortality, and only minor postoperative neurological deficits occurred in 7.5% of patients.

CONCLUSION

In a long-term follow-up period, 84.9% of the patients in the study could be evaluated as Engel Class I. The analysis of outcome showed that patients benefited significantly from early surgery and excision of the hemosiderin rim.

Supratentorial cavernous angiomas presenting with seizures: surgical outcomes in 60 consecutive patients

The aim of this study is to determine surgical outcomes and factors affecting seizure outcomes in patients who harbor supratentorial cavernous angiomas presenting with seizures. Sixty patients were classified into the intractable epilepsy group (n=22) and the sporadic seizure group (n=38) and then managed differently in accordance with our guidelines. Patients exhibiting sporadic seizures were treated by lesionectomy, except for patients harboring mesial temporal lesions. We performed lesionectomy, extended lesionectomy, standard temporal lobectomy and tailored resection on 33, 9, 9 and 9 patients, respectively. Finally, 72.7% (16/22) of patients with intractable epilepsy and 89.5% (34/38) of patients with sporadic seizures achieved Engel Class I outcomes. A long duration of illness was somewhat related to a poor outcome in patients with intractable epilepsy, yet this was not true of patients with sporadic seizures. Other factors which included age at onset, size of the lesions and locations were not related to seizure outcomes. The role of residual hemosiderin is yet to be discovered. A lesionectomy alone can be considered a reasonable approach for those patients who exhibit sporadic seizures and have an extra-temporal or neo-temporal lesion. In patients with intractable epilepsy and/or mesial temporal lesions, a more invasive approach could achieve the better seizure outcome.

Prediction of postoperative outcome with special respect to removal of hemosiderin fringe: A study in patients with cavernous haemangiomas associated with symptomatic epilepsy

PURPOSE

In this study 30 patients with symptomatic epilepsy caused by cavernomas were investigated in a postoperative follow up study to assess predictors for postoperative outcome with respect to indications, time and approach of surgery.

METHODS

Thirty patients with cavernomas refractory to medical treatment were scheduled for surgery based on the findings of high-resolution MR imaging and intensive EEG-video monitoring. Postoperative outcome of epilepsy was assessed by follow-up examinations based on the basis of classification by Engel and the International League against epilepsy (ILAE).

RESULTS

The following variables were associated with good postoperative outcome: (1) complete resection of hemosiderin fringe surrounding the cavernoma was correlated to less postoperative seizure frequency versus incomplete resection of the hemosiderin fringe according to the outcome protocol of ILAE. (2) Lower duration of epilepsy at the time of operation was correlated to a better postoperative outcome with a benefit for recovery. (3) Absence of hemorrhage before surgery and unifocal seizure onset was a predictor for a favorable outcome, whereas bilateral or multifocal seizure onset zones showed poorer postoperative outcomes. (4) In patients with dual pathology (hippocampal sclerosis in addition to a cavernoma), lesionectomy plus hippocampectomy as opposed to lesionectomy only, had a better outcome than single lesionectomy.

CONCLUSION

Postoperative outcome in patients with cavernomas should be the topic of further prospective multicenter studies involving a large number of patients. In addition to the ideal operation time and handling of dual pathology the role of extended resection including perilesional hemorrhages should be taken into account.

Drug-resistant temporal lobe epilepsy due to cavernous malformations

Object

Supratentorial cavernous angiomas may be associated with drug-resistant focal epilepsy. Surgical removal of the malformation may result in seizure control in a number of patients, although in most studies a long history and high frequency of attacks have been recognized as indicators of unfavorable seizure outcome. In the literature, there are no clear indications regarding the optimal diagnostic presurgical workup and the surgical strategy for this particular subgroup of patients with symptomatic epilepsy. In this paper the authors focus on the preoperative workup and the surgical management of the disease in eight consecutive patients undergoing surgery for drug-resistant temporal lobe epilepsy (TLE) due to cavernous malformations (CMs), and the relevant literature on this issue is also reviewed.

Methods

Preoperatively, all patients were assessed using a noninvasive protocol aimed at localizing the epileptogenic zone on the basis of anatomical, electrical, and clinical criteria. The presurgical assessment yielded an indication for lesionectomy in two cases, lesionectomy plus anteromesial temporal lobectomy in four cases, and lesionectomy plus extended temporal lobectomy in two cases. At follow-up examinations, seizure, neuropsychological, and psychiatric outcomes were all evaluated. Seven patients were categorized in Engel Class IA (seizure free), and one was categorized in Engel Class IB (occasional auras only). No adverse effects on neuropsychological or psychosocial functioning were observed.

Conclusions

Epilepsy surgery can be performed with excellent results in patients with intractable TLE caused by CMs. Noninvasive presurgical evaluation of these patients may enable a tailored approach, providing complete seizure relief in most cases.

Management of patients with cavernous angiomas presenting epileptic seizures

BACKGROUND

The aim of this study was to establish a treatment strategy for patients with cavernous angiomas and have seizures.

METHODS

We analyzed retrospectively 31 patients with cavernous angiomas presenting with seizures. Of the 31 patients, 15 (11 men, 4 women) had been treated medically (the medical group) and 16 (11 men, 5 women) had been treated surgically (the surgical group). The percentage of patients who became seizure-free and the number of anticonvulsants used were compared between these 2 groups. The mean follow-up period was 5.3 years (range, 7 months-10 years). There was no statistically significant difference between the 2 groups with regard to the number of patients, sex, age, and follow-up period.

RESULTS

The percentage of patients who became seizure-free was higher in the surgical group than in the medical group (80% vs 19%, P < .01). The number of anticonvulsants required was reduced in the surgical group after surgery (from 1.5 +/- 0.7 to 1.1 +/- 0.8, P < .01) and was not reduced after in the medical group.

CONCLUSIONS

Surgical intervention may have greater benefits than medical intervention for patients with cavernous angiomas presenting with epileptic seizures.

[Cerebral cavernomas, epilepsy and seizures. Natural history and therapeutic strategy]

PURPOSE

To review, from a retrospective series of 48 patients presenting with seizures associated with one or more supratentorial cavernoma(s), the natural history of the seizures and outcome according to medical and surgical treatment.

METHODS

Patients were divided into two groups: group A included patients presenting with a single seizure or rare seizures (n=21), and group B patients having intractable epilepsy (n=27). All received antiepileptic drugs and 35 were operated on (12 in the group A and 23 in the group B). Stereo-EEG was performed in 8 patients in group B. Surgery included lesionectomy alone (n=16), resection of the cavernoma and perilesional tissue (n=7) or tailored corticectomy including the cavernoma (n=12).

RESULTS

The natural history of seizures was different in the two groups: mean age at seizure onset was 25 years in group B and 33 years in group A (p<0.05), seizures were partial in all patients in group B and 8 patients in group A (p<0.05). Seizure frequency and periodicity also varied. Prolonged seizure-free periods were observed. The cavernoma was temporal in 17 patients in group B and 4 patients in group A (p<0.01). In group A, seizure outcome was favorable following surgery or with antiepileptic medication only (7 patients out of 12 operated were seizure-free, as were 5 out of 7 non-operated). In group B, seizure outcome was better after surgery than with medication only (17 patients out of 23 operated were in Engel's Class I, while 3 patients of 4 non-operated patients had persisting seizures despite antiepileptic polytherapy).

CONCLUSION

Variations in seizure severity in patients harboring cavernomas suggest different therapeutic approaches. In case of unique or rare seizures, surgical resection of the cavernoma is appropriate, but benefits of surgery over antiepileptic medication in terms of seizure control remains unclear. Intractable epilepsy associated with cavernomas is better controlled after surgery rather than with medication only. In these patients, a detailed preoperative work-up is necessary and should be followed by wide resection associated or not with corticectomy, especially in the temporal lobe. Evaluation of outcome after surgery should consider the surgical strategy, antiepileptic medications and the patient's seizure history.

Cavernous haemangiomas, epilepsy and treatment strategies

BACKGROUND

Cavernous haemangiomas (cavernomas) are benign vascular malformations which can be found at any region within the central nervous system. Epilepsy is the most frequent manifestation of this malformation. Magnetic resonance imaging (MRI) used for the diagnostic evaluation of symptomatic seizures is a sensitive and specific method for the detection of cavernomas. Due to an increased application of MR imaging in the diagnostic evaluation of symptomatic seizures cavernomas have been found with increasing frequency over the past years. To achieve optimal treatment of patients with cavernous haemangiomas and epilepsy both medical and surgical treatment have to be considered.

OBJECTIVE

This paper reviews published studies and presents our own results concerning current treatment schedules of epileptogenic cavernomas.

RESULTS

In patients with intractable epilpesies surgical treatment of cavernomas seems to be the most successful antiepileptic therapy. Whether microsurgical lesionectomy, including the removal of only the cavernoma, or a more extensive resection is needed to achieve this aim are discussed.

CONCLUSION

New data acquired with high-resolution imaging (MRI, PET) and electrophysiology indicate that magnetencephalography (MEG) may contribute to the delineation of epileptogenic tissue bordering the lesion, thus permitting appropriate inclusion of this specific area within the resection, instead of performing a simple lesionectomy.